Open Access

ARTICLE

OsMAPK6 Affects Male Fertility by Reducing Microspore Number and Delaying Tapetum Degradation in Oryza sativa L.

Wuzhong Yin^#, Hongxia Yang^#, Yantong Wang, Ping Feng, Yao Deng, Yang Liu, Danyang Chen, Yijie Ban, Weichi Liu, Guanghua He^*, Nan Wang^*

Key Laboratory of Application and Safety Control of Genetically Modified Crops, College of Agronomy and Biotechnology, Southwest University, Chongqing, 100715, China
# Wuzhong Yin & Hongxia Yang contributed equally to this work

* Corresponding Authors:Guanghua He. Email: ; Nan Wang. Email:

(This article belongs to the Special Issue: High-Yield Rice Physiology & Genetics)

Phyton-International Journal of Experimental Botany 2022, 91(4), 727-744. https://doi.org/10.32604/phyton.2022.017811

Received 08 June 2021; Accepted 05 August 2021; Issue published 09 December 2021

Abstract

The mitogen-activated protein kinase (MAPK) cascade is important in stress signal transduction and plant development. In the present study, we identified a rice (Oryza sativa L.) mutant with reduced fertility, Oryza sativa mitogen-activated protein kinase 6 (osmapk6), which harbored a mutated MAPK gene. Scanning and transmission electron microscopy, quantitative RT-PCR analysis, TUNEL assays, RNA in situ hybridization, longitudinal and transverse histological sectioning, and map-based cloning were performed to characterize the osmapk6 mutant. The gene OsMAPK6 was expressed throughout the plant but predominantly in the microspore mother cells, tapetal cells, and microspores in the anther sac. Compared with the wild type, the total number of microspores was reduced in the osmapk6 mutant. The formation of microspore mother cells was reduced in the osmapk6 anther sac at an early stage of anther development, which was the primary reason for the decrease in the total number of microspores. Programmed cell death of some tapetal cells was delayed in osmapk6 anthers and affected exine formation in neighboring microspores. These results suggest that OsMAPK6 plays pivotal roles in microspore mother cell formation and tapetal cell degradation.

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